Warning! Impulse attack!
Impulse attack means Shock Mine, Force Shell Cannon or anything else that moves your ship when it hits you. In my experience, these are rarely ever effective enough to actually worry about.
"Impulse" is a fancy physics word for "push" (force applied for some time).
Underneath the view of your own ship in the right of your cockpit, a small icon like this will appear when you're hit with an impulse attack:
